Two-Dimensional Lattices of VN: Emergence of Ferromagnetism and Half-Metallicity on Nanoscale

Two-dimensional (2D) ferromagnets with high spin-polarization ratio and high Curie temperature are crucial for developing next-generation spintronic nanodevices. Using first-principles calculations, we predict two polymorphic modifications (<i>t</i>-VN and <i>h</i>-VN) of 2D VN lattices that have robust intrinsic ferromagnetic properties and high Curie temperatures. Whereas <i>t</i>-VN has 99.9% of spin polarization at the Fermi level, <i>h</i>-VN possesses a half-metallic type of conductivity and keeps it after contact with semiconducting MoS₂, which can be used as the substrate for <i>h</i>-VN synthesis and valley polarized contacts. Magnetocrystalline anisotropy energy of 2D VN polymorphs is found to be at least an order larger than those of Fe and Ni bulks. The phonon spectra and ab initio molecular dynamic simulation prove that 2D VN lattices have a high thermodynamic stability. These advantages demonstrate that the VN monolayers should be promising candidates for low-dimensional spintronic devices

A complex of ceftriaxone with Pb(II): synthesis, characterization, and antibacterial activity study

<div><p>A Pb(II) complex with ceftriaxone (H₂Ceftria) antibiotic was synthesized by reaction of ceftriaxone disodium salt (hemi)heptahydrate with lead nitrate in water–ethanol medium. The complex was characterized on the basis of complexometric titration, spectrophotometric and thermogravimetric analyses, capillary electrophoresis, IR, Raman and UV–vis spectroscopies, and density functional theory calculations. Pb(II) is five-coordinate with distorted square pyramidal geometry. The coordination of Ceftria²⁻ to Pb(II) occurs through N and O of the triazine, lactam carbonyl, carboxylate, and amine groups. The antibacterial activity study showed that <i>Klebsiella pneumoniae</i> is resistant to [Pb(Ceftria)]·3H₂O. The antibacterial activity of [Pb(Ceftria)]·3H₂O against <i>Staphylococcus aureus</i> is reduced compared with ceftriaxone. In contrast, the antibacterial activity of [Pb(Ceftria)]·3H₂O against <i>Escherichia coli</i> is 28% higher than that of ceftriaxone antibiotic.</p></div